Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 54

Quote:

Originally Posted by AV Science Sales 5 

Took some measurements with Audyssey engaged. Subs only, no smoothing, dynamic EQ engaged and no boost added.


Left speaker and subs, Audyssey and dynamic EQ. 1/6 smoothing.

Mike - could we see those again but this time without Dynamic EQ?  Just for comparison purposes both with your own graphs and those of others (normally posted without DEQ in place).

Quote:

Originally Posted by sdrucker 

Hey guys,
After all this time, I got busy, and installed and set up my UMM-6 with the appropriate 90 degree cal file. The biggest obstacle was getting my laptop to stay on the Geoforce Nvidia HDMI-equipped card, rather than default to the mobile display and give me dead eight channel HDMI audio and mic. I tried Keith's 'incantation', and it didn't work until I picked the Geoforce with extended desktop on both laptop and my VT50 display. Argh.,...,

You  did do the incantation in Latin I assume?  This is one of the difficulties with using Windows I think - everyone has a different configuration of hardware and nobody can say for sure that what works for them will work for someone else - your Geoforce Nvidia being a case in point. Good sleuthing anyway...

I only care about the MLP so I have only being taking one measurement at the MLP for each speaker or speaker combination. I may try using three or four mic positions for each measurement at some stage to see if I get a much of a difference.

Quote:

I only had time earlier to run one for the subs with no Audyssey, output down 10 db for the sub LFE, and with no smoothing, there's a needle sharp 30 db null at 60 and approximately 90 Hz . I hope it goes away when I do more measurements and bring in my Mythos ST (currently at 80 Hz, but I'll be curious to see how they look at 60 as well) for full range at 1/6 or 1/12, with Audyssey engaged and DEQ off. And I'm only on battery power....with OM and L/R+sub plots post-Audyssey at 1/12, those dips were much milder (not even -5 db).

Don't forget Bill Fitzmaurice's 'Graphitis Nervosa' which basically, once infected, means you spend inordinately large amounts of time trying to correct or compensate for things that you can see clearly on graphs but cannot hear at all with your ears.  It will be interesting to see your graphs. BTW, I get some differences between my OM/Omnimic and my UMM-6/REW too. It seems the UMM-6/REW combination has more 'resolution' sometimes - maybe it's the calibrated mic. Or maybe REW is doing things a little differently. FWIW, I have more confidence in REW.

Quote:

Finally, is it good form to capture all speaker configurations of interest (e.g. L/R+subs) at a position and move on to the next position (then averaging each configuration by selectively picking the measurements), or getting all OCD and doing all X measurements by configuration, averaging, then moving on to the next configuration? I'd think the former, but as a REW neophyte, it doesn't hurt to check before I create 48 temporary files at one sitting LOL....

Does it make any difference?  One of the great things about REW IMO is that you can capture the measurement results and THEN do anything you like with them afterwards. But I haven’t used more than one mic position yet, so I haven't needed to do any averaging.

Quote:

Originally Posted by sdrucker 

Hey guys,
After all this time, I got busy, and installed and set up my UMM-6 with the appropriate 90 degree cal file. The biggest obstacle was getting my laptop to stay on the Geoforce Nvidia HDMI-equipped card, rather than default to the mobile display and give me dead eight channel HDMI audio and mic. I tried Keith's 'incantation', and it didn't work until I picked the Geoforce with extended desktop on both laptop and my VT50 display. Argh.,...,

Anyway, after running the Ratshack SPL to get 80 db, I came up with a noise floor in the mid-50s and maximum sensitivity of exactly 120 db. Should this be a concern, at the extreme of the 'normal' range?

Also, how many measurements are you guys taking to get a publishable average? Do you recommend concentrating on MLP or the Audyssey basic three to eight, if my focus is the three seats in the MLP?

I only had time earlier to run one for the subs with no Audyssey, output down 10 db for the sub LFE, and with no smoothing, there's a needle sharp 30 db null at 60 and approximately 90 Hz . I hope it goes away when I do more measurements and bring in my Mythos ST (currently at 80 Hz, but I'll be curious to see how they look at 60 as well) for full range at 1/6 or 1/12, with Audyssey engaged and DEQ off. And I'm only on battery power....with OM and L/R+sub plots post-Audyssey at 1/12, those dips were much milder (not even -5 db).

Finally, is it good form to capture all speaker configurations of interest (e.g. L/R+subs) at a position and move on to the next position (then averaging each configuration by selectively picking the measurements), or getting all OCD and doing all X measurements by configuration, averaging, then moving on to the next configuration? I'd think the former, but as a REW neophyte, it doesn't hurt to check before I create 48 temporary files at one sitting LOL....

To add a bit to Keith's response:

A noise floor of ~50dB is as good as it gets with this mic.  At this time, it is still unclear whether the higher noise floor (when compared with the balanced EMM-6, for example, which measures a noise floor of ~40dB) has any meaningfull impact on our measurements.  I would guess that the waterfall might be impacted, but I am not sure.

As far as a measurement average is concerned, IMO the average has limited value.  For example, when you are sitting in the MPL, what does an average response graph tell you about the sound you are hearing--nothing.  I think that since we believe Audyssey is somehow averaging the 8 measurement positions to produce the smoothest response over the listening area, perhaps an 8-position average using REW would give us some insight into what Audyssey is doing.  Perhaps this is true, but so what?  If you do take a number of REW measurements at points outside of the MLP, it might reveal one or more points that exhibit an undesirable response anomaly.  Such an anomaly, if at one of the 8 Audyssey measurement points, could be skewing the Audyssey calibration.  Knowing this, you could either try to correct the anomaly, or "game" Audyssey by avoiding the anomaly during your calibration. 

So, don't bother publishing the average.  IMO, here are the six most meaningful measurements to publish in your first go-around (all taken from the MLP, with Audyssey on and DEQ off):

- Left+Right+Subs, 15-20,000Hz, 1/6 smoothing.

- Center+Subs, 15-20,000Hz, 1/6 smoothing

- Bass response 15-300Hz, no smoothing (using one of the two measurements above)

- Waterfall 20-300Hz, (also using one of the first two measurements)

- Impulse ETC graphs for the Left and Right speakers, measured individually, 20-20,000Hz, with subs off.

The first three measurements reflect what you are actually hearing at the MLP.  For example, you never hear just the bass, or just the left speaker.  If this first set of graphs indicates issues that you want to understand and resolve, that is the time to start drilling down into the detailed measurements, isolating single speakers, etc.  Don't produce 48 measurements the first time around!

Of course, this is just my opinion, and I would enjoy hearing other viewpoints.

Quote:

Originally Posted by AustinJerry 

Quote:

Originally Posted by sdrucker 

Hey guys,
After all this time, I got busy, and installed and set up my UMM-6 with the appropriate 90 degree cal file. The biggest obstacle was getting my laptop to stay on the Geoforce Nvidia HDMI-equipped card, rather than default to the mobile display and give me dead eight channel HDMI audio and mic. I tried Keith's 'incantation', and it didn't work until I picked the Geoforce with extended desktop on both laptop and my VT50 display. Argh.,...,

Anyway, after running the Ratshack SPL to get 80 db, I came up with a noise floor in the mid-50s and maximum sensitivity of exactly 120 db. Should this be a concern, at the extreme of the 'normal' range?

Also, how many measurements are you guys taking to get a publishable average? Do you recommend concentrating on MLP or the Audyssey basic three to eight, if my focus is the three seats in the MLP?

I only had time earlier to run one for the subs with no Audyssey, output down 10 db for the sub LFE, and with no smoothing, there's a needle sharp 30 db null at 60 and approximately 90 Hz . I hope it goes away when I do more measurements and bring in my Mythos ST (currently at 80 Hz, but I'll be curious to see how they look at 60 as well) for full range at 1/6 or 1/12, with Audyssey engaged and DEQ off. And I'm only on battery power....with OM and L/R+sub plots post-Audyssey at 1/12, those dips were much milder (not even -5 db).

Finally, is it good form to capture all speaker configurations of interest (e.g. L/R+subs) at a position and move on to the next position (then averaging each configuration by selectively picking the measurements), or getting all OCD and doing all X measurements by configuration, averaging, then moving on to the next configuration? I'd think the former, but as a REW neophyte, it doesn't hurt to check before I create 48 temporary files at one sitting LOL....

 

To add a bit to Keith's response:

 

A noise floor of ~50dB is as good as it gets with this mic.  At this time, it is still unclear whether the higher noise floor (when compared with the balanced EMM-6, for example, which measures a noise floor of ~40dB) has any meaningfull impact on our measurements.  I would guess that the waterfall might be impacted, but I am not sure.

 

As far as a measurement average is concerned, IMO the average has limited value.  For example, when you are sitting in the MPL, what does an average response graph tell you about the sound you are hearing--nothing.  I think that since we believe Audyssey is somehow averaging the 8 measurement positions to produce the smoothest response over the listening area, perhaps an 8-position average using REW would give us some insight into what Audyssey is doing.  Perhaps this is true, but so what?  If you do take a number of REW measurements at points outside of the MLP, it might reveal one or more points that exhibit an undesirable response anomaly.  Such an anomaly, if at one of the 8 Audyssey measurement points, could be skewing the Audyssey calibration.  Knowing this, you could either try to correct the anomaly, or "game" Audyssey by avoiding the anomaly during your calibration. 

 

So, don't bother publishing the average.  IMO, here are the six most meaningful measurements to publish in your first go-around (all taken from the MLP, with Audyssey on and DEQ off):

 

- Left+Right+Subs, 15-20,000Hz, 1/6 smoothing.

- Center+Subs, 15-20,000Hz, 1/6 smoothing

- Bass response 15-300Hz, no smoothing (using one of the two measurements above)

- Waterfall 20-300Hz, (also using one of the first two measurements)

- Impulse ETC graphs for the Left and Right speakers, measured individually, 20-20,000Hz, with subs off.

 

The first three measurements reflect what you are actually hearing at the MLP.  For example, you never hear just the bass, or just the left speaker.  If this first set of graphs indicates issues that you want to understand and resolve, that is the time to start drilling down into the detailed measurements, isolating single speakers, etc.  Don't produce 48 measurements the first time around!

 

Of course, this is just my opinion, and I would enjoy hearing other viewpoints.

FWIW, I am doing it the way you recommended and it is fairly quick and painless and has produced useful, meaningful results for me, leading, so far, to the application of a few additional treatments (arriving next week). 

Someone in the 818 thread just asked what the difference was between Dynamic EQ and THX Loudness Plus, so when i measure next week I will do a comparison of the two and see what is going on. I find them to be virtually identical when listening, so it will be interesting to see if they are very different in the way the operate. They shouldn't be really as they are designed to do the same job - to compensate for human hearing as loudness varies, dynamically. I'll post the graphs here too if anyone is interested.

Quote:

Originally Posted by JChin 

Hi all, ran first test this morning following the guide and my graph don't look the same as the guide on page 50-52 ... it show a down slope at 40 Hz .

Which speakers are you testing there?  Can you post the graph again with the Legend showing so we can see?

A graph that shows a reasonably flat response from 20Hz to 20kHz will be one showing the response of, say, the RF + RL + Subs or C + Subs.

Your graphs don't seem to have the sub working at all. They appear to be RF, LF and C only.

Also, the agreed standard for posting graphs of the full spectrum is 15Hz to 20kHz, 1/6th smoothing. Can you readjust yours please?

EDIT: here's mine for RF + LF + C - not all that different to yours, broadly speaking:

And here is one showing C only + Subs:

Quote:

Originally Posted by JChin 

Quote:

Originally Posted by kbarnes701 

Which speakers are you testing there?  Can you post the graph again with the Legend showing so we can see?

A graph that shows a reasonably flat response from 20Hz to 20kHz will be one showing the response of, say, the RF + RL + Subs or C + Subs.

Your graphs don't seem to have the sub working at all. They appear to be RF, LF and C only.

Also, the agreed standard for posting graphs of the full spectrum is 15Hz to 20kHz, 1/6th smoothing. Can you readjust yours please?

Hi Keith, I'm having problem saving the graph w/legend as well and posting it here. I must be missing a few steps since I didn't have this problem when playing with the Audyssey mic last month.

You're correct, its showing only left, center and right only w/o the sub running.

The graph is set to 15Hz to 20kHz and 1/16 smoothing. I will try to capture the graph again to show the legend.

ATM the graph is set 6Hz to 30kHz. It isn’t important except it makes comparisons a little more difficult 'at a glance', hence Jerry's 'standards'.

As the graph is only showing RF + LF + C with no subs, then it is as expected. If you follow Jerry's Guide, there is a chart showing the standard basic measurements to take - follow that and you will have a full set that you can then manipulate in various ways. Remember that when you take RF, LF and C only, you need to physically switch off the subwoofer(s). To measure subwoofer only select Ch4 in REW Preferences. To measure RF + LF + Subs, select Chs 1 and 2 in REW Preferences. To Measure C + Subs, select Ch 3 only.

To save the Legend when you make a capture of a graph, tick the Legend Box as here:

Any text you type into the box below the tick boxes will appear at the top of your graph. 

Quote:

Originally Posted by JChin 

Ah, so my graph don't look like the guide (page 50-52) is because the sub is off.

Correct.

See above.

Quote:

Originally Posted by JChin 

Quote:

Originally Posted by kbarnes701 

To measure RF + LF + Subs, select Chs 1 and 2 in REW Preferences.

To perform this measurement, go into REW Preferences set Output as "Audio HDM OutI 1" , Timing Reference Output as "Audio HDMI Out 2" and leave the Subwoofer turned "on"?.

Yes. The sub will always play, due to bass management, unless you specifically turn it off with its power button.

Quote:

Originally Posted by Geronimo.USMC 

Quote:

Step 5: REW Microphone Calibration
Note: With certain USB microphones, calibration is not necessary. Currently, only the UMIK-1 is recognized by the REW beta software as having a sensitivity parameter that allows REW to calibrate the microphone automatically. All other microphones must be configured manually using this procedure.

Any idea, will REW ever have a sensitivity parameter that allows REW to calibrate the Spectrum UMM-6 microphone automatically? I want get the UMM-6....

Then get it - manual SPL calibration of the UMM-6 takes all of 5 seconds.... and loading the mic's cal file into REW takes even less time.

Quote:

Originally Posted by Geronimo.USMC 

Quote:

Originally Posted by kbarnes701 

Then get it - manual SPL calibration of the UMM-6 takes all of 5 seconds.... and loading the mic's cal file into REW takes even less time.

I'm thinking about it. Expect many questions from me lol.

Anyone want to sell me their Cross·Spectrum UMM-6?

Questions are good - they lead to answers!

Does anyone have the "cheat sheet" for HDMI settings for the various tests (e.g. R+Sub = input channel X and output channel Y etc)?  I know it was posted somewhere in here but I can't seem to locate it.  I suggest this be included in the guide as a reference if possible.

Quote:

Originally Posted by Geronimo.USMC 

I'm thinking about it. Expect many questions from me lol.

Anyone want to sell me their Cross·Spectrum UMM-6?

Guess it's time for me to move up from my RS meter. Suggestions for the EMM-6 (since I still have the usb pre)?

Thanks.

Michael

Quote:

Originally Posted by jkasanic 

Does anyone have the "cheat sheet" for HDMI settings for the various tests (e.g. R+Sub = input channel X and output channel Y etc)?  I know it was posted somewhere in here but I can't seem to locate it.  I suggest this be included in the guide as a reference if possible.

These are the channel designations in REW. You can use any combination of any two at one time. Sub(s) will always be active unless physically switched off.

Channels in REW:

1.     = FL

2.     = FR

3.     = C

4.     = Sub(s)

5.     = SL

6.     = SR

7.     = RSL

8.     = RSR

Quote:

Originally Posted by ack_bk 

Thank you so much for this guide! I followed it step-by-step with a Windows 7 laptop (hdmi and it recognizes 8 channels) and UMIK-1 mic and it could not have gone easier. I still have a lot to learn, but here is what I am getting with my 4 DIY subs in my room after running Audyssey XT:



No smoothing, all speakers set to small, mains crossed over at 80hz. My amp (iNuke3K DSP) has lots of EQ/filtering options, but I am pretty happy with what I am seeing (assuming I am reading this right).
Any thoughts?

Can you remake the graph following the guidelines in the Guide?  That is, we need to see 5dB steps on the left not 20dB, 15-300Hz unsmoothed for bass frequencies and 15Hz - 2-kHz 1/6 smoothed for full range. Thanks. You current graph is hiding too much detail in that 20dB spread.

Spoiler: you may be less happy with what you are seeing when you apply 5dB increments ;)

Thanks Keith...I'm really struggling getting HDMI to work.  I think this ASUS laptop that I just got also has a Realtek ASIO driver and I can't seem to get REW to recognize the prepro or mic (it worked yesterday when I did the ASIO4ALL install) even though both are set as default in the sound control panel.  I guess just to make things even more complicated, it is a Windows 8 machine.  HST, once you install the patch to get your start menu back, it feels a lot like Windows 7 under the hood.

Quote:

Originally Posted by jkasanic 

Thanks Keith...I'm really struggling getting HDMI to work.  I think this ASUS laptop that I just got also has a Realtek ASIO driver and I can't seem to get REW to recognize the prepro or mic (it worked yesterday when I did the ASIO4ALL install) even though both are set as default in the sound control panel.  I guess just to make things even more complicated, it is a Windows 8 machine.  HST, once you install the patch to get your start menu back, it feels a lot like Windows 7 under the hood.

I am using an Asus with the ASIO4ALL driver too and it works here, but I am using W7 not 8. If it worked once for you then it can work again I guess. I found I could only get it to work 100% reliably if I followed a strict procedure for cabling up and switching on, which I posted a fe posts back.